用悬液Wien效应探测阳离子在黄棕壤和黑土胶粒双电层中分布的初步研究  

Preliminary study of cation distribution in the electrical double layers of colloidal yellow-brown and black soil particles by Wien effect measurements

作　　者：程程[1,2] 李成保[2] 姜军[2] 徐仁扣[2] 周立祥[1] 

机构地区：[1]南京农业大学资源与环境科学学院,南京210095 [2]土壤和农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008

出　　处：《环境科学学报》2010年第5期1043-1051,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No. 40701079)~~

摘　　要：研究了采用悬液Wien效应测定反号离子在土壤胶粒双电层中分布的方法原理,及不同阳离子在黄棕壤和黑土胶粒双电层中的分布规律.试验条件下,这2种土壤的Na+饱和胶粒的表面电导率最大,而使表面电导率最小的阳离子是不同的,黄棕壤为Cu2+,黑土则为Cd2+.黄棕壤和黑土胶粒的表面电导率随阳离子的变化顺序分别为Na+>K+>Cd2+>Pb2+>Ca2+>La3+>Cu2+和Na+>K+>Pb2+>La3+>Cu2+>Ca2+>Cd2+.除Na+和Cd2+外,几乎所有阳离子在黄棕壤胶粒扩散层中的比率(ECS/ECad)明显小于黑土,其中Cd2+在黄棕壤和黑土胶粒扩散层中的比率分别为0.174和0.0872.黄棕壤和黑土胶粒的ζ电位随阳离子价型的变化顺序,除了钙饱和黑土外,与土壤胶粒表面电导率随阳离子价型的变化顺序完全一致.This paper describes the principle of determination of counter-ion distribution in the electrical double layers of colloidal soil particles by Wien effect measurements on soil suspensions,and the distribution of various cations in the double layers of colloidal yellow-brown and black soil particles. Under the experimental conditions,the surface electrical conductivities of colloidal soil particles saturated with Na＋ were the largest for both soils,whereas Cu2＋ and Cd2＋ counter ions resulted in minimum surface conductivities in the yellow-brown and black soils,respectively. The whole sequence was Na＋ K＋ Cd2＋ Pb2＋ Ca2＋ La3＋ Cu2＋ for yellow-brown soil and Na＋ K＋ Pb2＋ La3＋ Cu2＋ Ca2＋ Cd2＋ for black soil. For all cations besides Na＋ and Cd2＋ the ratio of cations in the diffuse layers to adsorbed cations,ECS/ECad,was significantly less for the yellow-brown soil particles as compared to that for the black soil particles. The ECS/ECad values of Cd2＋ for yellow-brown and black soil particles were 0.174 and 0.0872,respectively. The sequences of the ζ potentials of the colloidal particles of the two soils,except that of black soil particles saturated with Ca2＋,were similar to those of the surface electrical conductivities of the soil particles.

关 键 词：扩散层 动电电位 极化率 表面电导率 

分 类 号：X131[环境科学与工程—环境科学]